The rejuvenated "Star Wars" series, on a roll since "The Force Awakens" stormed into theaters in 2015, hits its first major stumbling block with "Solo: A Star Wars Story," a plodding trek through the backstory of Han Solo.

You know Han Solo: The rugged, gruff, charming space cowboy brought to life by Harrison Ford in the original "Star Wars" trilogy, and then offed in "The Force Awakens" (sorry, but the statute of limitations is up on "Force Awakens" spoilers). Here he's played by Alden Ehrenreich, a virtual unknown whose biggest role to date was in the Coen Brothers' 2016 comedy "Hail, Caesar!"

Filling the shoes of Ford is no enviable task — classic actor, classic role — and the biggest problem with "Solo" is you can't get Harrison Ford out of your head. Ehrenreich has a mischievous manner about him, but not the same wily yet honorable presence as Ford's Solo. You don't root for him in the same way, and there's a flatness to his performance -- and, to a larger extent, to "Solo" as a whole -- that doesn't invite you in.

Not that Ehrenreich has to live up to Harrison Ford or "Solo" needs to live up to "Star Wars," but in a way, they do. These are the parameters the modern "Star Wars" has set up for itself, and if you're going to give us a Han Solo standalone film, it better do more than trade on our collective nostalgia for the character and the "Star Wars" universe. "Solo" doesn't.

The Millenium Falcon in "Solo".

The Millenium Falcon in "Solo".

Lucasfilm Ltd.

It does give us Solo's background story, as he came up as a smuggler with dreams of being the best pilot in the galaxy. He is torn from his love, Qi'ra (Emilia Clarke, taking a break from her Khaleesi duties on "Game of Thrones'") while trying to slip some contraband through security at a space airport, and he winds up linking up with Tobias Beckett (Woody Harrelson), a shifty grifter who takes Han under his wing.

Along the way he makes acquaintances with "The Beast," a towering wookie who will come to be known as Chewbacca, and Lando Calrissian, a smooth talker and con man who's one of the galaxy's coolest cats. Played here by Donald Glover, Calrissian is an intriguing presence, but he doesn't seem like a character as much as he seems like a younger facsimile of Billy Dee Williams' original character, or at least our memories of him.

Donald Glover as Lando Calrissian in "Solo".

Donald Glover as Lando Calrissian in "Solo".

Jonathan Olley/Lucasfilm Ltd.

And that's the way much of "Solo" goes. Oh look, it's the Millennium Falcon! Listen closely, they're talking about Tatooine! Because "Star Wars" is held in such high regard in our culture — it's the most popular film franchise of all-time, hands down — there is a thirst among the fanbase for anything "Star Wars" related, and a desire by executives to keep the merry-go-round going. The movie's reason for being is obvious — outside of Luke Skywalker and Darth Vader, whose backstories were told at length in the exhausting "Star Wars" prequels, Solo is likely the biggest character in the "Star Wars" universe -- but "Solo" is too wobbly to stand on its own, and the story is too needlessly complex. Strip away the nostalgia, the familiar "Star Wars" backdrop and take it for what it's worth, and "Solo" is a bit of a clunker.

Director Ron Howard, stepping in for ousted "Lego Movie" creators Phil Lord and Christopher Miller, takes a while to find his grounding — an early confrontation between Solo and a water creature is near-disastrous — but he manages to stabilize by the third act. By then, father-son screenwriting team Lawrence and Jonathan Kasdan has established a familiar story of honor among thieves which hits on familiar beats of double crosses and surprise reveals. Up to that point, however, "Solo" drifts around the galaxy and has problems finding its bearings. And it never achieves that familiar, giddy "Star Wars" rush.

Donald Glover as Lando Calrissian and Phoebe Waller-Bridge as L3-37 in "Solo".

Donald Glover as Lando Calrissian and Phoebe Waller-Bridge as L3-37 in "Solo".

Lucasfilm Ltd.

The character who makes the biggest impression, oddly, is a bot named L3-37, voiced by Phoebe Waller-Bridge. L3-37 has a strong feminist agenda and her presence disrupts the familiarity of the "Star Wars" universe, in a good way. She's new to the audience and the story, she feels current and topical and she has a bit of bite, which is lacking from everything else in "Solo." In a sea of nostalgia, she's the one you remember.